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Commit 9b984dae authored by Keith Packard's avatar Keith Packard
Browse files

drm/i915: Check eDP power when doing aux channel communications 



Verify that the eDP VDD is on, either with the panel being on or with
the VDD force-on bit being set.

This demonstrates that in many instances, VDD is not on when needed,
which leads to failed EDID communications.

Signed-off-by: default avatarKeith Packard <keithp@keithp.com>
parent 47f0eb22

drivers/gpu/drm/i915/intel_dp.c

+22 −0
Original line number Diff line number Diff line
@@ -279,6 +279,24 @@ intel_hrawclk(struct drm_device *dev) 
	}

}



static void

intel_dp_check_edp(struct intel_dp *intel_dp)

{

	struct drm_device *dev = intel_dp->base.base.dev;

	struct drm_i915_private *dev_priv = dev->dev_private;

	u32 pp_status, pp_control;

	if (!is_edp(intel_dp))

		return;

	pp_status = I915_READ(PCH_PP_STATUS);

	pp_control = I915_READ(PCH_PP_CONTROL);

	if ((pp_status & PP_ON) == 0 && (pp_control & EDP_FORCE_VDD) == 0) {

		WARN(1, "eDP powered off while attempting aux channel communication.\n");

		DRM_DEBUG_KMS("Status 0x%08x Control 0x%08x\n",

			      pp_status,

			      I915_READ(PCH_PP_CONTROL));

	}

}



static int

intel_dp_aux_ch(struct intel_dp *intel_dp,

		uint8_t *send, int send_bytes,
@@ -295,6 +313,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, 
	uint32_t aux_clock_divider;

	int try, precharge;



	intel_dp_check_edp(intel_dp);

	/* The clock divider is based off the hrawclk,

	 * and would like to run at 2MHz. So, take the

	 * hrawclk value and divide by 2 and use that
@@ -408,6 +427,7 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp, 
	int msg_bytes;

	uint8_t	ack;



	intel_dp_check_edp(intel_dp);

	if (send_bytes > 16)

		return -1;

	msg[0] = AUX_NATIVE_WRITE << 4;
@@ -450,6 +470,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp, 
	uint8_t ack;

	int ret;



	intel_dp_check_edp(intel_dp);

	msg[0] = AUX_NATIVE_READ << 4;

	msg[1] = address >> 8;

	msg[2] = address & 0xff;
@@ -493,6 +514,7 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode, 
	int reply_bytes;

	int ret;



	intel_dp_check_edp(intel_dp);

	/* Set up the command byte */

	if (mode & MODE_I2C_READ)

		msg[0] = AUX_I2C_READ << 4;